An apparatus has been built for the servo-control of working contractions of isolated frog skeletal muscle within an NMR spectrometer. 31P and 1H NMR spectra are obtained of repetitively contracting muscle. During the past year efforts have been directed at (1) determining intracellular buffering power as a function of pH from the 1H and 31P spectra, and (2) obtaining and validating anisotropic water diffusion coefficients from GSLIM processed diffusion images.